Navi: A New Open-Source VR Input Sol. using your smartphone

nice! How do you link the head vs slingshot rotation i.e. how do you determine whether you turned or only looked in a direction (your shoulder pivots in the first case and not in the second)? It is possible to have similar rotation-only scheme even with a gyro mouse, that enables also mobile support, see here https://www.youtube.com/watch?v=fbV1rUXUFXI

So, the head and slingshot are not actually linked together. I send the gyro data of the phone to the PC and so when I rotate in my chair both my head and the phone are rotating (and thus affecting their IMU's) so I can update them independently. However, if I am siting still and I just rotate my head, then since the phone did not move in physical space, the virtual object does not move either.

Ok, then I must be misunderstanding something. I guess that since you only have rotational data, you will pivot the the slingshot around a specific point in the Unity coordinate system depending on its rotation. In my case, since the default scenario is right hand, I had to put that ppint near the character's shoulder/elbow, which is to the right of the character's vertical axis. However, I see that you hold the phone in front of you with both hands, so your pivot point is in the center of the character, so you have no such complication.

Correct, I am rotating about the camera in order to achieve this effect. I am assuming the case your talking about is the video you posted, which is a bit more complicated I think because you would have to move the virtual camera in order to make sure your gyro mouse stays on the screen.